This invention relates to egg processing in general and, in particular, to a method of, and apparatus for, breaking shell eggs at a high rate on an industrial scale.
Industrially, most eggs to be converted to egg products are broken by high speed mechanical breakers. These machines separate the yolk and albumen, the latter being more commonly known as the white. As heretofore constructed, the egg breakers have had several drawbacks limiting their production rates.
One of the drawbacks arises in connection with the feeding of shell eggs into the breaker. A typical conventional feeding scheme has been such that shell eggs to be broken are first washed on an infeed conveyor, from which they are loaded directly on respective egg breaker assemblies mounted at longitudinal spacings on a looped conveyor of the breaker. A difficulty has been encountered in thus loading the eggs on the breaker assemblies in the correct attitude. Unless loaded correctly, the eggs cannot be cut and severed in the middle portion of each egg by the breaker assemblies, making difficult the thorough recovery of the white and yolk therefrom. The higher the rate is made at which eggs are loaded on the breaker assemblies from the infeed conveyor, the more improperly are they positioned on the breaker assemblies. Thus the conventional feeding practice has been a bottleneck in the high speed processing of eggs.
Another problem is the incomplete recovery of egg contents. Generally, in egg breakers of the type under consideration, shell eggs are held recumbently by the respective breaker assemblies. Each breaker assembly has a pair of knives movable toward and away from each other. Held against each other, the pair of breaker knives cut into a shell egg at its midpoint from below and then move apart to separate the shell into two pieces, thereby causing the white and yolk to drop into a recovery cup assembly. All the shell eggs are not necessarily broken in the intended manner, however, as some of them may be held by the breaker assemblies in other than the correct recumbent attitude. Part of the white or even the yolk may remain in the broken shells. Such residues have heretofore been discarded with the shells.
An obvious solution to this problem is to apply forced streams of air into the broken eggshells while they are still being carried by the breaker assemblies. The residual liquid will be blown out of the shells for recovery in the underlying recovery cup assemblies. This solution is not so easy to practice as it may seem, however, for the following reasons.
The egg breaker assemblies are mounted as aforesaid on the looped breaker conveyor. While traveling at constant speed along the looped path, the breaker assemblies receive shell eggs from the infeed conveyor, break them, and have their shells unloaded. The recovery of the residual liquid from the broken shells must be performed on the traveling breaker assemblies at some stage between the breaking of the shell eggs and the unloading of the broken shells. It is uneconomical, or rather totally impractical, to mount sources of pressurized air on the breaker conveyor for the respective breaker assemblies. Perhaps the only practical scheme is to provide air nozzles on the breaker conveyor for the respective breaker assemblies and to supply pressurized air to the nozzles while the breaker assemblies are traveling through a predetermined region along the breaker conveyor path. A difficulty arises, however, in such controlled supply of pressurized air to the traveling nozzles from a fixed source. A rotary valve would do if the nozzles revolved about a single axis. The breaker conveyor turns around several sprockets or like wheels and so inhibits the use of a simple rotary valve. No satisfactory alternative has so far been suggested, so that the pneumatic recovery of the residues from broken eggshells has just been a paper plan.
The known high speed egg breakers have also had difficulties with regard to the recovery cup assemblies designed to separate the white and yolk. Each recovery cup assembly comprises a yolk cup just under one of the egg breaker assemblies on the breaker conveyor, and an albumen cup underlying the yolk cup. The yolk cup receives both white and yolk from the broken egg and allows the white to flow out of a recess cut in its side wall.
In the yolk cup of prior art design, the recess has not been well adapted for the complete outflow of the white, often allowing part of the white, particularly the dense albumen, to remain in the yolk cup along with the yolk. It is also a disadvantage that the recess has been so positioned on the yolk cup that the recovered yolk is discharged therefrom through the recess. The yolk on flowing through the recess has been easy to have its enclosing membrane broken and thus to smear the cup, necessitating its cleaning. Of course the yolk cup remains unsmeared if the yolk is discharged intact.
Furthermore, the conveyor for transferring the eggs in the conventional apparatus has a plurality of pairs of convex rolls parallel to each other on which each egg is supported and transferred to the successive process.
However, in such a pair of convex rolls, if the eggs are extremely large, they cannot be supported stably on the rolls and sometimes they fall down from the rolls because the size of the rolls is fixed or unchangeable.